JP2012152283A - Biological signal detection apparatus and bed-departure prediction detecting system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a biological signal detection apparatus that can detect a biological signal depending on the difference in sleeping postures.SOLUTION: The biological signal detection apparatus includes: pressure sensors (piezoelectric sensors) 11R, 11L disposed across on a bed B; and sensor interfaces 12R, 12L provided for respective pressure sensors (piezoelectric sensors) 11R, 11L, and processing output signals of corresponding pressure sensors (piezoelectric sensors) and generating the biological signal indicative of at least a breathing signal, a pulse wave signal, and a body motion signal.

Description

  The present invention relates to a biological signal detection apparatus that detects a biological signal in a human sleeping posture and a bed leaving sign detection system that detects a sign of bed leaving based on the biological signal detected from the biological signal detection apparatus.

  2. Description of the Related Art Conventionally, there is known a biological signal detection device that is disposed on a bed such as a bed or a futon and detects biological signals such as human respiration, pulse waves, body movements, and snoring. In such a biological signal detection apparatus, the detected biological signal is used for detecting, for example, a person's bed.

  In such a biological signal detection device, for example, a sensor such as (i) a pressure sensor or (ii) a piezoelectric sensor is used to detect a biological signal.

(I) In the case of a biological signal detection device (pressure sensor type) using a pressure sensor The detection of a biological signal by the pressure sensor type is performed by detecting a change in pressure in a space that is isolated from the surrounding pressure. Is called. In order to form this space, for example, an air mat filled with air is used.

  This air mat functions as a film that isolates the surrounding pressure and creates a shielded space. The air mat is formed of a plastic resin material such as polyvinyl chloride, polyethylene, polypropylene, and high molecular compound silicone so that vibration waves of the human body, direct vibration, and the like can be transmitted to the internal space. When the air mat is placed on a bed such as a bed or futon (hereinafter referred to as a bed), it should be placed near the upper body so that a biosignal can be detected no matter where the person moves on the bed. Placed transversely.

  FIG. 9A is a diagram illustrating an example of a biological signal detection apparatus using a conventional pressure sensor. The pressure sensor is disposed in the air mat. FIG. 9B is a diagram showing another example of a biological signal detection device using a conventional pressure sensor. As described above, the pressure sensor may be disposed outside the air mat via an air tube such as a vinyl tube drawn out from the air mat.

  FIG. 10A is a diagram illustrating an example of an internal circuit of the pressure sensor. In this internal circuit, the electret film directly captures the pressure. This electret film converts a change in pressure as a change in charge, and converts a minute change in the capacitance C1 into a voltage across the both ends. This change in the voltage across the capacitor C1 is discharged through the resistor R1, resulting in a voltage change amount of time constant C1 × R1. The amount of change in the voltage across the capacitor C1 is output as a voltage signal. This voltage signal becomes the gate voltage of Q1 which is a junction type FET (Field effect transistor), and the voltage change amount is converted into the drain current change amount by the common source amplifier circuit. In this internal circuit, the diode D1 is provided to prevent the gate voltage of the junction FET Q1 from dropping too much.

In this pressure sensor, the output voltage (V _out ) can be expressed by the following equation (2) based on the following equation (1). Incidentally _{I D} is a drain _{current, I DSS} is the drain saturation output current, _{V p} is the gate pinch-off voltage, _{V G} is the voltage applied to the _{gate, V out,} the pressure sensor , V _DD is the power supply voltage, and R2 is the resistance value of the resistor R2.

  FIG. 10B is a conceptual diagram showing an example of the structure of the pressure sensor. This pressure sensor is configured as a pipe having a pressure hole formed at one end and a mechanism that releases excessive pressure at the other end. In the pressure sensor, a front washer, an electret film, a gap washer, and an electrode are disposed on the pressure hole side, and a back chamber is formed in the remaining space.

  In this pressure sensor, the pressure input from the pressure hole side is applied to the electret film through the pressure hole. And in a pressure sensor, the capacity | capacitance C1 of an electret film changes by the clearance gap between the electrode which is a reference electrode, and an electret film changing. Further, in the pressure sensor, when the capacitance C1 changes, as shown in FIG. 10A, the gate voltage of the junction FET Q1 is set via the resistor R1.

  In the biological signal detection apparatus having the above components, one pressure signal in which a plurality of biological signals such as pulse waves, breathing, snoring, and body movements are synthesized is detected from the pressure sensor when a human sleeps on the air mat. can do. In the biological signal detection device, the presence / absence of sleep, sleep / shallowness / deep sleep, etc. are analyzed by analyzing the state of posture such as landing / leaving, etc. Detect state.

(Ii) In the case of a biological signal detection apparatus (piezoelectric sensor type) using a piezoelectric sensor The detection of a biological signal by a piezoelectric sensor is performed by detecting strain applied to the sensor by the stress of an object.

  FIG. 11 is a diagram illustrating an example of a biological signal detection apparatus using a conventional piezoelectric sensor. In this biological signal detection device, the biological signal detection unit is constituted by an upper panel, a lower panel, and a piezoelectric sensor sandwiched between both panels. Both panels and the piezoelectric sensor are arranged transversely in the vicinity of the upper body so that a biological signal can be detected no matter where the person moves on the bed, like the pressure sensor described above.

  FIG. 12A is an external view illustrating an example of the configuration of the piezoelectric sensor, and FIG. 12B is a diagram illustrating an example of an internal circuit of the piezoelectric sensor. This piezoelectric sensor is made of a ceramic such as barium titanate or lead zirconate titanate. Such a material is an element having mechanical reversibility, but when used as a piezoelectric sensor, it is configured to detect mechanical stress as an electrical signal.

  The piezoelectric effect is generally expressed as the following formula (3) and the following formula (4), but when functioning as a piezoelectric sensor, the following formula (4) is used. S is strain, s is elastic compliance constant, T is stress, d is piezoelectric constant, E is electric field, D is electric flux density, and ε is ratio Dielectric constant.

  Such a piezoelectric sensor is distorted by the stress generated on the panel when a person lies on the top panel, and this strain synthesizes a plurality of biological signals such as pulse wave, respiration, body motion, and squealing. It can be detected as stress. In the biological signal detection device, the state of posture such as landing or getting out of the body, for example, the state of posture such as landing or getting out of the body, and further analyzing the biological signal, the sleep state such as whether there is sleep or light sleep Is detected. This mechanical stress is output as Vout to the equivalent circuit of FIG.

  Japanese Patent Application Laid-Open No. 2008-284001 proposes a biological signal detection apparatus using a piezoelectric sensor with good installation and storage.

JP 2008-284001 A

  In the conventional pressure sensor type and piezoelectric sensor type biosignal detection devices as described above, since they are arranged transversely in the vicinity of the upper body on the bed, it is possible to detect landing or getting out of the detected biosignal. Although it is possible, it is impossible to detect a human sleeping posture or a sleeping position in a bed. As a result, when the conventional biological signal detection device is used, it is possible to detect the biological signal only under the condition of sleeping in a resting posture.

  FIG. 13 is a diagram illustrating an example of a biological signal (a respiratory signal, a pulse wave signal, and a body motion signal) detected by a conventional biological signal detection device. In the conventional biological signal detection device, it is detected that there is a bed leaving due to a change in the body motion signal.

  Here, the actual sleeping posture is other than sleeping in a resting sleeping posture, and the sleeping posture is roughly classified into three types. First, the sleeping posture in which the human is positioned on the left side (wall side) when viewed from the front of the bed (see FIG. 14A), and then the sleeping posture in which the human is positioned on the right side (floor side) when viewed from the front of the bed (See FIG. 14 (b)). Finally, the sleep posture (see FIG. 14 (c)) in which the human is located in the center when viewed from the front of the bed. These three types of sleeping postures are greatly different in human movements (leaving behavior) when getting out of bed from each sleeping posture.

  However, the sleep posture cannot be identified from the change in the waveform of the biological signal in FIG. That is, in the conventional biological signal detection device, a change in sleep posture can be grasped as a change in body motion signal, but one of the sleep postures shown in FIGS. 14 (a) to 14 (c). Cannot be detected. In addition, FIG. 14 is a figure which shows the human sleeping posture on the bed by a prior art.

  For this reason, in the case of using a conventional biological signal detection device to detect a sign of getting out of the care recipient, which is indispensable in nursing care or the like, for example, when a sleeping posture as shown in FIG. 14 and the biological signal detected in the sleeping posture as shown in FIGS. 14 (a) and 14 (c) cannot be identified, and thus the detection of getting out of bed may be erroneously detected. Can not be excluded.

  As described above, in the conventional biological signal detection device, it is only possible to identify the presence or absence of a bed, and it is not possible to detect different bed movement behaviors depending on the sleeping posture, so there is a limit to increasing the detection accuracy of a bed leaving sign. .

The present invention has been made in consideration of the above points, and an object of the present invention is to provide a biological signal detection device capable of detecting a biological signal due to a difference in sleeping posture.
Another object of the present invention is to provide a bed leaving sign detection system that can detect a bed leaving sign with high accuracy by detecting a change in the detected sleep posture.
That is, this invention is comprised from the following technical matters.

(1) a plurality of pressure sensitive sensors arranged in a direction crossing the bed surface;
A filter unit that is provided for each of the pressure sensors, processes output signals of the corresponding pressure sensors, and generates at least biological signals indicating respiratory signals, pulse wave signals, and body motion signals;
A biological signal detection apparatus comprising:

  According to (1), since a biological signal can be generated for each of a plurality of pressure-sensitive sensors arranged, for example, a human sleeping posture on a bed can be detected.

  (2) In (1), the pressure sensor is a pressure sensor or a piezoelectric sensor.

  According to (2), since the pressure-sensitive sensor is a pressure sensor or a piezoelectric sensor, it can be installed on a bed or the like, for example, and a plurality of biological signals can be acquired from one signal output from the sensor. .

(3) In (1) or (2), the pressure-sensitive sensor is
Two symmetrically arranged on the bed surface,
Corresponding to the bed leaving position of the bed surface, one is defined as the bed leaving side, and the other is defined as the non-bed leaving side,
When there is a change in the bed leaving position, the arrangement is reversed to cope with it.

  According to (3), even if the bed leaving position is reversed, it is not necessary to change the setting of software, for example, only by changing the position of the pressure-sensitive sensor in accordance with the bed leaving position. Versatility can be improved.

(4) The biological signal detection device according to (1) to (3),
A sleep posture specifying unit that specifies a sleep posture based on a biological signal for each of the pressure sensors generated by the filter unit;
A bed leaving sign detection unit that detects a bed leaving sign signal indicating a sign of bed leaving based on a change in sleep posture specified by the sleep position specifying unit;
A sign detection system for getting out of bed.

  According to (4), it is possible to detect a bed leaving sign with high accuracy by detecting a change in the detected sleep posture.

  According to the present invention, a biological signal due to a difference in sleep posture can be detected. According to another aspect of the present invention, it is possible to detect a sign of getting out of bed with high accuracy by detecting a change in the detected sleep posture.

It is a block diagram which shows the structure of a bed leaving sign detection system. It is a schematic diagram which shows one example of the biosignal detection apparatus which concerns on this invention. It is a schematic diagram which shows the example of arrangement | positioning of the air mat and a pressure sensor in the installation condition of a bed. It is a filter system figure in a living body signal detecting device. It is a figure which shows the human sleeping posture on the bed by this invention. It is a figure which shows the change of the waveform of a biomedical signal in each sleep posture. It is a figure which shows the waveform of a bed leaving operation and a rollover operation. It is a figure which shows the other example of arrangement | positioning of an air mat and a pressure sensor. It is a figure which shows one example of the biosignal detection apparatus using the conventional pressure sensor. It is a figure which shows one example of a structure of the conventional pressure sensor. It is a figure which shows one example of the biosignal detection apparatus using the conventional piezoelectric sensor. It is a conceptual diagram which shows an example of the conventional piezoelectric sensor. It is a figure which shows an example of the biosignal detected in the conventional biosignal detection apparatus. It is a figure which shows the human sleeping posture on the bed by a prior art.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing the configuration of the bed leaving sign detection system S. As shown in FIG.
The bed leaving sign detection system S is a system that detects a sign of bed leaving from a change in the sleeping posture of a person on a bed (bed B in the present embodiment) such as a futon or a bed. As shown in FIG. 1, the bed leaving sign detection system S includes biological signal detection devices 1 and 2 and a CPU 3.
In such a bed leaving sign detection system S, the CPU 3 detects a bed leaving sign (operation before leaving the bed) based on the biological signal detected by the biological signal detection devices 1 and 2. When the present bed leaving sign detection system S is used for management of a care recipient in nursing care, for example, the detection result of the bed leaving sign is displayed on a display unit (not shown), and notification to the manager is performed. It can cope with caregiver's getting out of bed.

As shown in FIG. 1, the biological signal detection device 1 is configured to be able to identify the location of a sensor that detects a human biological signal as right-side signal processing, and as a right-side signal processing, a pressure sensor 11R and a sensor interface 12R.
On the other hand, the biological signal detection device 2 is configured to be able to identify the location of a sensor that detects a human biological signal as signal processing for the left side, and includes a pressure sensor 11L and a sensor interface 12L.

  The pressure sensor 11 outputs a change in pressure as a pressure signal. In the present embodiment, the pressure sensor 11 is disposed symmetrically on the bed B, and is provided with a pressure sensor 11R disposed on the right side and a pressure sensor 11L disposed on the left side. Details of the configuration of the pressure sensor 11 will be described later.

  The sensor interface 12 (filter unit) performs signal processing to detect the pressure signal output from the pressure sensor 11 as each biological signal, and outputs the result of this signal processing to the CPU 3. In the present embodiment, the sensor interface 12 is provided with a sensor interface 12R corresponding to the pressure sensor 11R and a sensor interface 12L corresponding to the pressure sensor 11L.

  In the case of right-side signal processing (left-side signal processing), the sensor interface 12R (sensor interface 12L) performs signal processing 1 (signal processing 4) so as to output a pulse wave signal, and outputs a respiratory signal. Thus, signal processing 2 (signal processing 5) is performed, and signal processing 3 (signal processing 6) is performed so as to output a body motion signal. Details of the signal processing in the biological signal detection devices 1 and 2 will be described later.

  FIG. 2A is a diagram showing a state in which the air mat M and the pressure sensor 11 of the biological signal detection devices 1 and 2 according to the present invention are arranged on the bed B. FIG.

  The air mat M functions as a film that creates a shielding space that is isolated from the surrounding pressure. Such an air mat M is formed of a plastic resin material such as polyvinyl chloride, polyethylene, polypropylene, and high molecular compound silicone so that vibration waves of the human body, direct vibration, and the like can be transmitted in the internal space. . In the present embodiment, the air mat M is provided with an air mat M (Right) corresponding to the pressure sensor 11R and an air mat M (Left) corresponding to the pressure sensor 11L.

  Here, the pressure sensor 11 is disposed in the air mat M. Therefore, the pressure sensor 11 outputs a change in the pressure of air in the air mat M, which is a sealed space isolated from the ambient pressure, as a pressure signal. For example, the pressure sensor 11 can take the configuration of the conventional pressure sensor 11 described above.

  As shown in FIG. 2A, the air mat M and the pressure sensor 11 are arranged with two sets spaced apart so as to cross the bed B in the vicinity of the upper body on the bed B.

  FIG. 3A is a diagram showing a state in which the air mat M and the pressure sensor 11 are arranged on the bed B installed in a place where the left side is the wall side and the right side is the floor side. As described above, in the present embodiment, the air mat M and the pressure sensor 11 are arranged on the bed B installed in a place where the left side is the wall side and the right side is the floor side. The present bed leaving sign detection system S can be used even when the right side is the wall side and the left side is the floor side. The use in the situation where the right side is the wall side and the left side is the floor side will be described in detail later.

In the bed B installed in such a place, the wall side (non-bed-off side) of the bed B is a side that is not likely to fall from the bed B, and is a direction that is not suitable for getting out of the bed. On the other hand, the floor side (the floor leaving side) of the bed B is the side that may fall from the bed B, and is the direction facing the floor. Specifying human movement in these directions is particularly important for grasping the behavior of the cared person, and it is important to know falling or getting out of bed in advance.
As described above, the biosignal detection devices 1 and 2 are configured to be able to identify the pressure sensors 11R and 11L. That is, in this embodiment, it is possible to identify whether the pressure sensor 11 is disposed on the right side (wall side) or the left side (floor side). Therefore, as described above, when the characteristics regarding getting out of the floor are different between the wall side and the floor side, the getting out of the bed can be detected with higher accuracy.

  Here, details of signal processing in the bed leaving sign system S will be described. FIG. 4 is a filter system diagram in the biological signal detection apparatuses 1 and 2. In the following, the right signal processing will be described with reference to FIG. The left-side signal processing is the same as the right-side signal processing, and a description thereof will be omitted.

  First, in the bed leaving sign system S, for example, when a human lands on the right air mat M (biological signal detection device 1), a plurality of pressure signals output from the right pressure sensor 11R (sensor 1R in FIG. 4) are output. A biological signal is synthesized (polymerized) and output as one signal.

  The first amplifier AMP1R for the sensor interface 12R demultiplexes (distributes) the input one pressure signal to a filter corresponding to each biological signal (pulse wave signal, respiratory signal, and body motion signal) to be extracted. Specifically, the pressure signal is demultiplexed by the filter Filter1R in order to extract the pulse wave signal. Further, the pressure signal is demultiplexed by the filter Filter2R in order to extract a respiration signal. The pressure signal is demultiplexed by the filter Filter 3R in order to extract the body motion signal. In addition, regarding the extraction of the pulse wave signal, the detection process is performed by the detector 1R after the filter Filter1R. Each filter Filter 1R, 2R, 3R is band-limited so that a signal in a frequency band corresponding to the biological signal from which the demultiplexed pressure signal is output is extracted.

Thereafter, the second sensor interface amplifier 12R amplifier AMP2R amplifies the extracted signal and outputs the pulse wave signal (R) as Signal1R. The pulse wave signal is output via the low-pass filter LPF1R after being amplified by the second sensor interface 12R amplifier AMP2R.
The third sensor interface 12R amplifier AMP3R amplifies the extracted signal and outputs the respiration signal (R) as Signal2R.
The fourth sensor interface 12R amplifier AMP4R amplifies the extracted signal and outputs the body motion signal (R) as Signal3R.

  Next, the relationship between the sleep posture and the biological signal will be described. FIG. 5 is a diagram showing a human sleeping posture on the bed B according to the present invention, (a) is a diagram showing a sleeping posture positioned on the left side (wall side) when viewed from the front of the bed B, (B) is a figure which shows the sleep posture located in the right side (floor side) seeing from the front of the bed B, (c) is a figure which shows the sleep posture located in the center of the bed B. Moreover, FIG. 6 is a figure which shows the change of the waveform of a biological signal in each sleep posture, (a) is a figure which shows the change of the waveform of a biological signal in the sleep posture of FIG. 5 (a), (B) is a figure which shows the change of the waveform of a biological signal in the sleep posture of FIG.5 (b), (c) shows the change of the waveform of a biological signal in the sleep posture of FIG.5 (c). FIG.

  For example, a sleep posture in which a human is sleeping on the right air mat M (biological signal detection device 1), that is, a waveform of each biological signal in a sleep posture as shown in FIG. 5B will be described. In the sleep posture shown in FIG. 5 (b), as shown in FIG. 6 (b), a human is sleeping on the right air mat M (Right), and pressure is applied to the right pressure sensor 11R. Therefore, on the left side (Left), almost no change in the waveform of the respiratory signal and the pulse wave signal is seen, and no body motion signal is detected. On the other hand, on the right side (Right), the waveform of each signal is high.

  Moreover, the change of the waveform of each signal when a bed leaving action is performed from the sleep posture illustrated in FIG. 7A and 7B are diagrams illustrating waveforms of the bed leaving operation and the turning operation. FIG. 7A is a diagram illustrating waveforms of signals when the user leaves the sleeping posture illustrated in FIG. 5B, and FIG. It is a figure which shows the waveform of each signal at the time of turning over from the sleep posture shown to 5 (a) to the state of FIG.5 (b).

  First, when leaving the sleeping posture shown in FIG. 5 (b), as shown in FIG. 7 (a), the person is sleeping on the right air mat M (Right), Since pressure is applied to the pressure sensor 11R, on the left side (Left), almost no change in the waveform of the respiratory signal and pulse wave signal is seen, and no body motion signal is detected. On the other hand, on the right side (Right), the waveform of each signal is high.

  When leaving from this sleep posture, a pressurization signal (positive voltage) serving as a sign of getting out of bed is detected in the right side (Right) body motion signal. A signal (negative direction voltage) is detected. At this time, other biological signals (pulse wave signal and respiratory signal) are not detected because the contact between the human body and the air mat M is not performed due to getting out of bed. That is, it is possible to detect a signal related to a series of signal changes on the right side as shown in FIG. In particular, in the present embodiment having a wall on the left side, a sign of getting out of bed can be detected with higher accuracy.

  Next, the change in the waveform of each signal when turning over from the sleep posture shown in FIG. 5A to the sleep posture shown in FIG. 5B will be described with reference to FIG. FIG.7 (b) is a figure which shows the waveform of each signal at the time of turning over from the sleep posture of Fig.5 (a).

As shown in FIG. 7 (b), since the person is lying on the left air mat M (Left) and the left pressure sensor 11L is under pressure, on the right side (Right), the respiratory signal and A change in the waveform of the pulse wave signal is hardly seen, and no body motion signal is detected. On the other hand, on the left side (Left), the waveform of each signal is high. From such a state, in the body movement signal, the waveform changes on the right side (Right) after the left side (Left), so the wall side: left side (Left) to the floor side: right side (Right). It can be detected.
Conversely, when the waveform changes on the right side (Right) from the state in which the waveform of each signal is high on the right side (Right), there is a case where the signal moves further to the floor side, that is, leaves the floor. The change in this signal can be regarded as a sign of getting out of bed.

  As described above, the bed leaving sign system S has been described with reference to the case where the wall is on the left side and the floor is on the right side as viewed from the front of the bed B as shown in FIG. However, the situation where the actual bed B is arranged is that the relative position direction of the wall and the bed B is opposite, that is, the wall is on the right side when viewed from the front of the bed B, as shown in FIG. There are also cases where the floor is on the left. In this case, the bed leaving sign system S reverses the positions of the biological signal detection devices 1 and 2, that is, the air mat M (Right) and pressure sensor used on the right side as shown in FIG. 11R and the air mat M (Left) and the pressure sensor 11L used on the left side are reversed as shown in FIG. 3B (the air mat M (Left) and the pressure sensor 11L on the right side, and the air mat M (Right) on the left side. ) And the pressure sensor 11R). Since the biological signal detection devices 1 and 2 are configured to be usable in the two cases described above, the signal processing is handled by hardware in addition to complicated operations such as mode setting and setting errors caused thereby. Is also a concern. Therefore, in the biological signal detection apparatus according to the present invention, the combination of the two air mats M and the pressure sensors 11R and 11L is changed to the definition of the wall side and the floor side, depending on the arrangement direction of the bed B and the wall (floor). The arrangement direction of the air mat M and the pressure sensor 11 can be changed. Specifically, the air mat M can be used even if it is reversed in the horizontal direction.

Hereinafter, other arrangement examples of the air mat M and the pressure sensor 11 will be described.
In the above-described biological signal detection apparatus according to the present invention, two sets (even numbers) of independent air mats M and pressure sensors 11 are arranged side by side so as to cross the bed B. A plurality of them may be provided.
In the biological signal detection apparatus according to the present invention, for example, as shown in FIG. 8A, four sets of air mats M and pressure sensors 11 arranged side by side across the bed B are provided in the longitudinal direction of the bed B. When configured in this manner, it becomes possible to identify four sleep postures on the wall side, on the floor side, on the wall side, and on the floor side, thereby improving the accuracy of detection of getting out of bed.

  Further, in the biological signal detection apparatus according to the present invention, when the bed B is wide, as shown in FIG. 8B, three sets (odd number) of air mats M and pressure sensors 11R across the bed B, The same effect can be obtained with 11C and 11L. When configured in this manner, it is possible to identify three sleep postures on the wall side, the center of the bed B, and the floor side, and the accuracy of detection of getting out of bed can be improved.

The biological signal detection devices 1 and 2 configured as described above include pressure sensors 11R and 11L and sensor interfaces 12R and 12L.
A plurality of pressure sensors 11R and 11L are arranged in a direction crossing the bed B.
The sensor interfaces 12R and 12L are provided for the pressure sensors 11R and 11L, process the output signals of the corresponding pressure sensors 11R and 11L, and display at least a biological signal indicating a respiratory signal, a pulse wave signal, and a body motion signal. Are generated respectively.

  Therefore, since the biological signal can be generated for each of the pressure sensors 11R and 11L arranged on the left and right in the biological signal detection devices 1 and 2, the human sleeping posture on the bed B can be detected. Further, in the biological signal detection devices 1 and 2, the sensors for acquiring the biological signals are the pressure sensors 11R and 11L, so that they may be installed on a bed or the like, and the frequency band is limited from the acquired one signal. By doing so, a plurality of biological signals can be acquired.

Two pressure sensors 11R and 11L are symmetrically arranged on the bed B, and one of the pressure sensors 11R and 11L is defined as the wall side and the other as the floor side corresponding to the bed B leaving position.
Therefore, in an environment where the arrangement direction of the bed B and the wall and floor is reversed, it is not necessary to change the signal processing hardware and software by changing (inverting) the positions of the air mat M and the pressure sensors 11R and 11L. Can be used.

The bed leaving sign detection system S includes biological signal detection devices 1 and 2 and a CPU 3.
The CPU 3 identifies the sleep posture based on the biological signal for each of the pressure sensors 11R and 11L generated by the sensor interfaces 12R and 12L, and indicates the sign of getting out based on the change in the identified sleep posture. Is detected.

In the bed leaving sign detection system S configured as described above, the following effects can be generally obtained.
The sign of getting out of bed of a care recipient in a care facility or the like may be based on a wake-up from the upper body on the bed B or may be a roll-over on the bed B. In either case, whether the sign behavior of leaving the bed is performed on the wall side or on the floor side is to detect the danger of complete leaving the bed B or falling from the bed B. There is a big difference.
However, in the bed leaving sign detection system S, it is possible to detect whether the bed leaving sign is detected from the pressure sensor 11L on the wall side where there is no danger, or on the contrary, from the pressure sensor 11R on the floor side where the danger is high. The accuracy of predictive detection can be dramatically improved.

  In the above-described embodiment, the preferred embodiment of the present invention has been described above. However, the present invention can be in a form in which various modifications are added to the above-described embodiment without departing from the spirit of the present invention.

  In the above-described embodiment, the example in which the pressure sensor 11 is used as the sensor of the biological signal detection devices 1 and 2 has been described. it can. In this case, the piezoelectric sensor can be applied to the present system by replacing the air mat M with the panel and the pressure sensor 11 with the piezoelectric sensor. FIG. 2B is a view showing a state in which the panel and the piezoelectric sensor of the biological signal detection devices 1 and 2 according to the present invention are arranged on the bed B. As in the case of the air mat M and the pressure sensor 11, the panel and the piezoelectric sensor are arranged in the direction across the bed B in the vicinity of the upper body on the bed B.

  In the above-described embodiment, a pressure sensor or a piezoelectric sensor is used as a sensor for detecting a biological signal. However, the present invention is not limited to this, and various pressure-sensitive sensors can be used.

1, 2 Biological signal detection device 3 CPU (sleep posture specifying part, bed leaving sign detection part)
11R, 11L Pressure sensor, piezoelectric sensor (pressure sensor)
12R, 12L sensor interface (filter part)
B bed (bed surface)
S bed leaving sign detection system

Claims (4)

A plurality of pressure sensors arranged in a direction crossing the bed surface;
A filter unit that is provided for each of the pressure sensors, processes output signals of the corresponding pressure sensors, and generates at least biological signals indicating respiratory signals, pulse wave signals, and body motion signals;
A biological signal detection apparatus comprising:   The biological signal detection device according to claim 1, wherein the pressure-sensitive sensor is a pressure sensor or a piezoelectric sensor. The plurality of pressure sensitive sensors are
Two symmetrically arranged on the bed surface,
Corresponding to the bed leaving position of the bed surface, one is defined as the bed leaving side, and the other is defined as the non-bed leaving side,
The biosignal detection device according to claim 1 or 2, wherein when the bed leaving position is changed, the arrangement is reversed. The biological signal detection device according to any one of claims 1 to 3,
A sleep posture specifying unit that specifies a sleep posture based on a biological signal for each of the pressure sensors generated by the filter unit;
A bed leaving sign detection unit that detects a bed leaving sign signal indicating a sign of bed leaving based on a change in sleep posture specified by the sleep position specifying unit;
A sign detection system for getting out of bed.

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